Question

HELP ME? Show me how to do the work also - Calculate the speed of an 8.0 x 10^4 kg airliner with a kinetic energy of 1.1 x 10^9 J.

Answer 1

Above my pay grade, but don't you need a drag coefficient and altitude/atmospheric pressure to calculate this? They both effect speed.

Answer 2

Or is this equation, "static in a vacuum"

Answer 3

we are assuming no external forces.

let K = kinetic energy, m = mass, V = velocity/speed

\[K = \frac{ 1 }{ 2 }m V^2\]
\[1.1 * 10^9 = \frac{ 1 }{ 2 }8.0*10^4* V^2\]

solve for V

Answer 4

I got this
\[1.1 x 10^9 = 1/2*8.0*10^4\]
\[1100000000=0.5*8000\]
\[1100000000 = 4000\]
\[524.4 \]

Did I do this right? Answers say its 1.7 x 10^2? Am I right?

Answer 5

i get 1.658* 10^2

Answer 6

\[V = \sqrt{\frac{ 1,100,000,000 }{ 0.5*80,000 }} = \sqrt{27500}\]
but you should really enter 1.1 E 9 in your calculator (1.1 * 10^9)

if you can't find the button, i can help.

Answer 7

Thank you, I understand now(: Could you help me with another problem?

Answer 8

ya

Answer 9

What is the speed of a 0.145 kg baseball if the kinetic energy is 109 J? I used the same equation and got 31.61 . I think I made a mistake. Answers say 38.8

Answer 10

i get 38.77

\[K = \frac{ 1 }{ 2 }m V^2\]
\[V = \sqrt{\frac{ 2K }{ m }} = \sqrt{\frac{ 2*109 }{ 0.145 }}\]

Answer 11

How did you get the 2K? Thats the part I don't understand?

Answer 12

i'm just isolating V from:\[K = \frac{ 1 }{ 2 }m V^2\]
multiply both sides by 2:\[2K = mV^2\]divide both sides by m\[\frac{ 2K }{ m } = V^2\]

Answer 13

what level calc is this problem from? wondering when I can look forward to these equations.

Answer 14

he multiplied both sides by 2 to clear the fraction

Answer 15

this equation is from mechanics or general physics.

you will most likely be taking this class in the same time as cal 1

Answer 16

I can't take physics or mech until concurrent with calc 2

Answer 17

that is different that here ^_^.

probably means you will be going straight into applying integration to basic physics.

early physics classes here don't require calculus

Answer 18

I need help with two more problems if thats okay?